The present invention relate to an electronic component, and more particularly to a dielectric resonator device, a dielectric filter, a composite dielectric filter, a synthesizer, a distributor, and a communication device including the same, each of which operates in a multimode.
A dielectric resonator in which an electromagnetic wave in a dielectric is repeatedly totally-reflected from the boundary between the dielectric and air to be returned to its original position in phase, whereby resonance occurs is used as a resonator small in size, having a high unloaded Q (Q0). As the mode of the dielectric resonator, a TE mode and a TM mode are known, which are obtained when a dielectric rod with a circular or rectangular cross section is cut to a length of sxc2x7xcexg/2 (xcexg represents a guide wavelength, and s is an integer) of the TE mode or the TM mode propagating in the dielectric rod. When the mode of the cross section is a TM 01 mode and the above-described s is equal to 1, a TM01xcex4 mode resonator is obtained. When the mode of the cross section is a TE01 mode and s is equal to 1, a TE01xcex4 mode dielectric resonator is obtained.
In these dielectric resonators, a columnar TM01xcex4 mode dielectric core or a TE01xcex4 mode dielectric core are disposed in a circular waveguide or rectangular waveguide as a cavity which interrupts the resonance frequency of the dielectric resonator, as shown in FIG. 26.
FIG. 27 illustrates the electromagnetic field distributions in the above-described two mode dielectric resonators. Hereupon, a continuous line represents an electric field, and a broken line a magnetic field, respectively.
In the case where a dielectric resonator device having plural stages is formed of dielectric resonators including such dielectric cores, the plural dielectric cores are arranged in a cavity. In the example shown in FIG. 26, the TM016 mode dielectric cores of (A) are arranged in the axial direction, or the TE01xcex4 mode dielectric cores of (B) are arranged in the same plane.
However, in such a conventional dielectric resonator device, to provide resonators in multi-stages, it is needed to position and fix plural dielectric cores at a high accuracy. Accordingly, there has been the problem that it is difficult to obtain dielectric resonator devices having even characteristics.
Further, conventionally, TM mode dielectric resonators each having a columnar or cross-shaped dielectric core integrally formed in a cavity have been used. In a dielectric resonator device of this type, the TM modes can be multiplexed in a definite space, and therefore, a miniature, multistage dielectric resonator device can be obtained. However, the concentration of an electromagnetic field energy to the magnetic core is low, and a real current flows through a conductor film formed on the cavity. Accordingly, there have been the problem that generally, a high Qo comparable to that of the TE mode dielectric resonator can not be attained.
It is an object of the present invention to provide a dielectric resonator device comprising resonators small in size, having plural stages, and to provide a multimode dielectric resonator device having a high Qo.
Moreover, it is another object of the present invention to provide a dielectric filter, a composite dielectric filter, a synthesizer, a distributor, and a communication device, each including the above-described multimode dielectric resonator.
In the multimode dielectric resonator device of the present invention, as defined in claim 1, a dielectric core having a substantial parallelepiped-shape is arranged substantially in the center of a cavity having a substantial parallelepiped-shape, and a TM01xcex4-x mode where a magnetic field is rotated in a plane parallel to the y-z plane of x, y, z rectangular coordinates, and a TM01xcex4-y mode where magnetic field is rotated in a plane parallel to the x-z plane are produced. Further, as defined in claim 2, a TM01xcex4-x mode where a magnetic field is rotated in a plane parallel to the y-z plane, and a TM01xcex4-y mode where a magnetic field is rotated in a plane parallel to the x-z plane, and a TM01xcex4-z mode where a magnetic field is rotated in a plane parallel to the x-y plane are produced. As described above, since the dielectric core having a substantial parallelepiped-shape is disposed substantially in the center of the cavity having a substantial parallelepiped-shape, the concentration degree of an electromagnetic energy onto the dielectric core is enhanced, and a real electric current flowing through the cavity becomes fine. Accordingly, the Qo can be enhanced. Moreover, though the dielectric core and the cavity are single, respectively, two or three TM modes can be utilized, and the miniaturization as a whole can be realized.
In the multimode dielectric resonator device, as defined in claim 3, a dielectric core having a substantial parallelepiped-shape is arranged substantially in the center of a cavity having a substantial parallelepiped-shape, a TM01xcex4-x mode where an electric field is rotated in a plane parallel to the y-z plane of x, y, z rectangular coordinates, and a TE01xcex4-y mode where an electric field is rotated in a plane parallel to the x-z plane are produced. Further, as defined in claim 4, a TE01xcex4-x mode where an electric field is rotated in a plane parallel to they z plane of x, y, z rectangular coordinates, a TE01xcex4-y mode where an electric field is rotated in a plane parallel to the x-z plane, and a TE01xcex4-z mode where an electric field is rotated in a plane parallel to the x-y plane are produced. Like this, though the mode is a TE mode, multiplexing, that is, duplexing or triplexing can ge realized, and the miniaturization as a whole can be performed.
In the multimode dielectric resonator device of this invention, as defined in claim 5, the above-described duplex or triplex TM mode and the duplex or triplex TE mode are produced by means of the dielectric core and the cavity which are single, respectively. Accordingly, a dielectric resonator device employing a TM mode and a TE mode can be obtained. Further, the dielectric resonator device, since it has a multimode, that is, at least quadruplex mode, can be further miniaturized as a whole.
When each of the above-described multiplexed resonance modes is used independently without the respective resonance modes being coupled to each other, a circuit including plural resonators such as a band rejection filter, a synthesizer, a distributor, or the like can be formed by use of a single dielectric core so as to be small in size.
In the multimode dielectric resonator device of this invention, as defined in claim 6, the resonator is rendered a multistage by coupling predetermined modes of the respective modes of the dielectric resonator device defined in any one of claims 1 to 5. Thereby, a resonator device is formed in which plural dielectric resonators are connected in a multistage. For example, a dielectric resonator device having a band-pass type filter characteristic can be obtained. Further, by coupling some of the plural resonance modes sequentially, and setting the other resonance modes to be independent, a filter in which a band-pass filter and a band-rejection filter are combined can be formed.
According to the present invention, as defined in claim 7, a dielectric filter is formed by providing an externally coupling means for externally coupling a predetermined mode of the dielectric resonator device.
According to the present invention, as defined in claim 8, formed is a composite dielectric filter including a plurality of the dielectric filters and having at least three ports.
According to the present invention, as defined in claim 9, a synthesizer comprises externally coupling means for externally coupling to plural predetermined modes of the dielectric resonator device, respectively, independently, and commonly externally coupling means for externally coupling to plural predetermined modes of the multimode dielectric resonator device in common, wherein the commonly externally coupling means is an output port, and the plural independently externally coupling means are input ports.
According to the present invention, as defined in claim 10, a distributor comprises independently, externally coupling means for externally coupling to plural predetermined modes of the dielectric resonator device, respectively, independently, and commonly externally coupling means for externally coupling to plural predetermined modes of the dielectric resonator device in common, wherein the commonly externally coupling means is an input port, and the plural independently externally coupling means are output ports.
Moreover, according to the present invention, as defined in claim 11, a communication device is formed of the above composite dielectric filter, a synthesizer, and a distributor provided in a high frequency section thereof